Guard for rock drills



Jan. 18, 1938. w. A. SMITH. SR GUARD FOR ROCK DRILLS Fil ed June 4, 1936 H's ATTORNEY.

Patented Jan. 18, 1938 warren mm groan? GUARD FOR, ROCK DRILLS William A. Smith, Sr., Athens, Pa., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application June 4, 1936, semi No. 83,431

3 Claims.

This invention relates to rock drills, and more particularly to a guard for the front end of a rock drill.

One object of the invention is to prevent the entrance of abrasive material into the front end of the rock drill.

Another object is to enable the guard to be conveniently attached to the rock drill and maintained securely in assembled position.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and forming a part thereof and in which similar reference numerals refer to similar parts,

Figure 1 is an elevation, in section, of a rock drill equipped with a guard constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 22, and

Figure 3 is a side elevation of the guard and a portion of the rock drill.

Referring more particularly to the drawing, the invention is shown applied to a rock drill of the type employed for up-hole drilling and comprising a cylinder 23, a front head 2! and a front cylinder washer 22. The washer 22 is interposed between the cylinder and the front head and extends into each to centralize these elements with respect to each other.

The cylinder 20 has a piston chamber 23 containing a reciprocatory hammer piston 24 for delivering blows to a working implement 25 extending into the front head 2!. In the construction shown the blows of the hammer piston 24 are transmitted to the working implement 25 by an anvil block 26 slidable in the front cylinder wash-er 22.

The rock drill may be provided with any suitable rotation mechanism for rotating the working implement 25. That shown, for the sake of simplicity of illustration, comprises a shaft 27 extending through the casing parts. On the shaft is a pinion 28 that meshes with teeth 29 on a chuck 30 which serves as a guide for the working implement 25. The shaft 2'! may be connected to be rotated by a suitable motor (not shown) which may be located at the rear end of the rock drill.

The guard constructed in accordance with the practice of the invention and designated 3| consists of resilient material, preferably rubber. It is of cup-shape and is seated on an end 32 of the chuck 30 extending beyond the corresponding end of the front head 2 i. The guard has an internal flange 33 which seats against the end surface of the chuck 30 and forms a bounding surface for a recess 34 in the guard and into which the end 32 of the chuck extends.

The flange 33 is located intermediate the ends of the guard, and in the front or uppermost wall 35 of the guard is an aperture 36 through which the working implement 25 extends. The aperture 36 is of the same cross sectional form as the working implement, although preferably of slightly smaller area so that when the working implement is inserted into the guard the walls of the aperture 36 will snugly engage the surface of the working implement and thus form an effective seal to prevent the admission of abrasive substances into the guard and the front end of the rock drill. The end wall 35 of the guard is joined to the flange 33 by an annular wall 31.

On the end of the guard adjacent the front head is a skirt 38 of annular shape which encircles and overlaps the front end of the front head 3| for a short distance so that water and cuttings flowing along the surface of the guard Will be diverted from the front end of the drill. The skirt 38 is of larger diameter than the front head 2| in order to prevent contact between the two.

The diameter of the recess 34 may, if desired, be slightly smaller than that of the projecting end 32 of the chuck so that when the guard is placed on the chuck the two will be in firm frictional engagement with each other. Preferably, however, the two are suitably interlocked with each other as by providing the guard, in the plane of the recess 34, with introverted key portions 39 to engage slots 40 in the surface of the chuck 30. As an additional precaution to prevent separation between the guard and the chuck the cooperating surfaces of the recess 34 and of the chuck may be covered with a suitable agglutinant 40 to bond these elements together.

In practice the present invention has been found to be a highly effective device for sealing the front end of a rock drill. Being resilient, the guard is capable of withstanding the severe usage to which devices of this character are subjected and the initial sealing engagement between the guard and the surface of the working implement may be maintained for prolonged periods of time unaffected by relative movement between the Working implement and the guard.

I claim:

1. In a rock drill, the combination of a rotary casing and a working implement extending thereinto, a resilient hollow guard having a Wall at one end to encircle the working implement and being in sealing engagement with the working implement, and means on the guard interlockingly engaging the casing to prevent rotary movement of the guard with respect to the casing.

2. In a rock drill, the combination of a casing and a working implement extending thereinto, a resilient hollow guard seated on the end of the casing and having a wall to encircle and snugly engage the working implement, and a skirt on the guard encircling and being spaced from the casing.

WILLIAM A. SMITH, SR. 

